Basic Cell Phone Cover design

Hi, I have an online business that creates custom cell phone cover designs. We are currently ordering covers from US suppliers. Its difficult to find covers that fit our needs, so we need to have one designed and a prototype created. The cover I have in mind is similar to the ones that are attached. It would be for the iPhone 4 and 5. We use a printer to get the image on the cover, so we have a limited amount of printable area. Flat surface only. The sides of the cover would be multiple colors and would made out of Thermoplastic Polyurethane "TPU". The back portion of the cover would be made from Poly-carbonate Plastic "PC" and would only be white in color. The cover would be 2 materials but molded together. Designed in solid works is preferred but not required.